The present invention relates to the characterization of a petroleum or refinery stream.
Since distillation is a fundamental separation process for the petroleum refining industry, it is essential to be able to characterize a crude oil or refinery stream based on its boiling behavior in the refinery units. Lab scale distillations are relatively slow and costly. Thus, simulated distillation by gas chromatography (GC) has been widely used in the petroleum industry to predict boiling yield. It is an important tool to provide information for parameter setting of the distillation process during refining.
GC Simulated Distillation as practiced in prior art uses a non-polar column (that elutes the molecules based on boiling point) and a flame ionization detector. However, recent developments in GC technology has advanced the separation from conventional one-dimensional (1D) separation (such as boiling point) to comprehensive two-dimensional (2D) separation (such as boiling point and polarity). Comprehensive two-dimensional gas chromatography (2DGC or GC×GC) technique can be applied to simulated distillation. If a hydrocarbon detector such as flame ionization detector (FID) is used, the most significant advantage is that the total yield curve and sub-total yields of each compound class such as saturates, one-ring aromatics, two-ring aromatics, and three aromatics can be determined. If an element-selective detector such as a sulfur chemiluminescence detector (SCD) is used, the sulfur compound classes such as mercaptan/sulfide/thiophene, benzothiophene, and dibenzothiophene) can be determined in additional to the total yield. Likewise a nitrogen specific detector (with 2DGC) could be used to determine the boiling yields of the individual classes of nitrogen containing molecules such as aliphatic amines, pyrrols, indoles, and carbazoles.